When light rays enter from one medium to another, refraction takes place. Consider refraction of light at a spherical surface separating two media of refractive indices n and `n_2 (n_2 > n_1)`.In the above case let the first medium be air and the second medium glass of refractive index 1.5, R of spherical surface = 20cm. An object is placed in air 100cm from the glass surface. At what position the image is formed?